Shin Hyebeom, Yang Eunseong, Kim Yong-Hoon, Kwak Min-Gi, Kim Youngmin
Display Research Center, Korea Electronics Technology Institute, 25 Saenariro, Bundang-gu, Seongnam 13509, Korea.
School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Korea.
Nanomaterials (Basel). 2021 May 10;11(5):1250. doi: 10.3390/nano11051250.
In response to the increasing demand for flexible devices, there is increasing effort to manufacture flexible electrodes. However, the difficulty of handling a thin film is an obstacle to the production of flexible electrodes. In this study, a heat-induced peelable pressure-sensitive adhesive (h-PSA) was fabricated and used to manufacture a flexible electrode with sub-tenth micron thickness. Unlike the control PSA, the incorporation of amide groups made the h-PSA fail through adhesive failure at temperatures ranging from 20 to 80 °C. Compared to the peeling adhesion (1719 gf/in) of h-PSA measured at 20 °C, the value (171 gf/in) measured at 80 °C was decreased by one order of magnitude. Next, the 8 μm thick polyethylene terephthalate (PET) film was attached on a thick substrate (50 μm) via h-PSA, and Mo/Al/Mol patterns were fabricated on the PET film through sputtering, photolithography, and wet-etching processes. The thick substrate alleviated the difficulty of handling the thin PET film during the electrode fabrication process. Thanks to the low peel force and clean separation of the h-PSA at 80 °C, the flexible electrode of metal patterns on the PET (8 μm) film was isolated from the substrate with little change (<1%) in electrical conductivity. Finally, the mechanical durability of the flexible electrode was evaluated by a U-shape folding test, and no cracking or delamination was observed after 10,000 test cycles.
随着对柔性器件需求的不断增加，制造柔性电极的努力也日益加大。然而，处理薄膜的困难是柔性电极生产的一个障碍。在本研究中，制备了一种热致可剥离压敏胶粘剂（h-PSA），并用于制造厚度在亚十分之一微米的柔性电极。与对照压敏胶粘剂不同，酰胺基团的引入使得h-PSA在20至80°C的温度范围内通过胶粘剂失效而失效。与在20°C下测得的h-PSA的剥离粘附力（1719 gf/in）相比，在80°C下测得的值（171 gf/in）降低了一个数量级。接下来，通过h-PSA将8μm厚的聚对苯二甲酸乙二酯（PET）薄膜附着在厚基板（50μm）上，并通过溅射、光刻和湿蚀刻工艺在PET薄膜上制备Mo/Al/Mo图案。厚基板减轻了电极制造过程中处理薄PET薄膜的困难。由于h-PSA在80°C时具有低剥离力和干净分离的特性，PET（8μm）薄膜上金属图案的柔性电极与基板分离时，电导率变化很小（<1%）。最后，通过U形折叠试验评估了柔性电极的机械耐久性，在10000次试验循环后未观察到开裂或分层现象。
